How to focus a Spatial on a Cam?

Development
1

hello everybody  :), look at the following images directly please.





Figure 1





Figure 2





Figure 3



these are three effects from different angles , but the effect I required is like the first image above.

I mean , whatever I change the location , I want it always show me one effect like the Figure 1. is there have any way ?

thanks.

2

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ortho mode?

ok…How to achieve it. :?

3

What you want is known as ortho mode… jmonkeyengine.com/wiki/doku.php/ortho?s[]=ortho



Unfortunately I'm not familiar enough with jME3 to know if it works the same as in 2

4

I guess u are looking for billboard. Here is quite useful link:

http://www.lighthouse3d.com/opengl/billboarding/



And this is how I implemented it in my code:


      public void updateLogicalState(float tpf) {
         float distance = getLocalTranslation().distance(startPoint);
         Vector3f toObj = camera.getLocation().subtract(
               getLocalTranslation()).normalizeLocal();
         Vector3f toObjXZ = new Vector3f(toObj.x, 0, toObj.z);
         float angle = Vector3f.UNIT_Z.angleBetween(toObj);
         Vector3f upAux = toObj.cross(Vector3f.UNIT_Z).normalizeLocal();
         Quaternion rotation = new Quaternion().fromAngleAxis(-angle, upAux);
         rotation.multLocal(new Quaternion().fromAngleAxis(
               (distance / MAX_RANGE) * FastMath.TWO_PI, Vector3f.UNIT_Z));
         angle = toObj.angleBetween(toObjXZ);

         setLocalRotation(rotation);
}



Also it should be possible to write a shader for this, and probably JME3 already has billboards support(At the time I wrote code above it did not).